Telephone-exchange system



E. R. LUNDIUS.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED FEB. 2a. 1915.

1,330,201 Patented Feb. '10, 1920.

3 SHEETS-SHEET E. R. LUNDIUS.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION man FEB. 28. 1918.

1 ,330,201 Patented Feb. 10, 1920.

3 SHEETS-SHEET 2.

E. R. LUNDIUS.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB. 28, IQIB.

-1 ,330,201 Patented Feb. 10,1920.

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I l Arr} UNITED STATES PATENT 0mm; 1

ERIC n. LUNDIUS, or BROOKLYN, NEW YORK, ASSIGNOR r0 WESTERN ELECTRIC COMPANSLINCORPOBATED, on NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE svs'rmvr.

' Specification of Letters Patent. 7 Patented Feb. 10, 1920,

Application filed February 28, 1918. Serial No. 219,602.

T 0 all whom; it may concern Be it known that I, Enio R. LUNpiUs, a citizen of the United States, residing at Brooklyn, in the county of Kings, State of New York, have invented certain newand useful Improvements in Telephone-EX- change Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to such systems of the central energy. .type in which trunk circuits are employed in 00111- pleting connections between telephone lines terminating at different switchboards.

An object of this invention is the-provision of improved signaling means for such systems. v

In accordance with a feature of this'invention, apparatus, provided in a trunk circuitextending from a B to a desk operators v osition, functions when the desk operator answers, touprevent the application to the trunk circuit of ringing current from a connected automatlc rlnging trunk circuit when the A operator subsequently connects with the out oing end of the auto- I I I O o inatic r nging trunk circult. v

In accordance w th another feature of this invention, the connected trunk ClIOultS are provided with apparatus by means'o'f j which the desk operator may signal the A operatorover the connected trunkcircuits.

For a more complete understanding' of this invention, reference should be had to the following description considered in connection with the accompanying drawings,

. desk operatorsposition. Thejtrunk circuit D; is jack-ended at the desk operators position,'at which is provided a cord circuit'E,-

by means of which the; desk operator may 8 andfthe plug 7 to ground.

answer a call incoming over theconnected link circuit B and trunk circuits C and D from the telephone line A. The automatic ringing trunk circuit C may connect with-a trunk circuit F (see Fig. 3), which at the desk operators position terminates in a switch or key by means of which the desk operator may answer incoming calls. The apparatus shown to the left of the dotted line 4:-4' is associated with the A opera tors position, that shown between the 'dotted lines 44 and 5 5, with the B operators position, and that shown to the right of the dotted line 5'5, withv the desk operators position.

Subscriber A. having initiated a call in the usual manner, and the link circuit B,

having been connected therewith in any desired manner, the A operator may actuate listening key 6 to connect the operators telephone set therewith. Upon. being advised that subscriber A desires to be connected with a'line terminating at another switchboard, thev Aoperator' restores the listening key 6 to normal position and communicates over an order wire circuit (not shown) with the B operator of the second switchboard and receives the trunk assignment. I V 7 7. Assuming trunk circuit C to be that assigned, the A operator inserts plug 7 of the link circuit B into jack 8 of the trunk circuit C, whereupon calling supervisory lamp 9 is lighted over a circuit from ,battery through the lamp 9, resistance 10, sleeve contacts of the plug 7 and the jack 8 and resistance 11 to ground. Trunk relay 12 is also operated over a circuit from battery through the winding of calling super visory relay 13, ring contacts of the plug 7 and th-ejack 8, right-handv winding of the trunk relay 12 and tip contacts of the jack The calling supervisory relay 13 does not now operate, due to the high resistance of the right-hand winding ofthe trunk relay 12. If the B operator] has not inserted plug 14 into: a jack .of another circuit, the'operation of the trunk rela y 12fcauses' lamp15i to be lighted over a circuit from battery through the lamp 15, contact of trunk; relayf12, lower normal contact of. relay 16 andresistance 17 y to ground. The lighting of the lamp indicates to the B operator that connection has been made with the assigned trunk circuit.

The B operator may now connect the plug 14 with the ack of the wanted line. However, if the number of the Wanted line has been changed or if the wanted line'is' to receive some unusual service, the B operator will find in the multiple jack of the line called, a d signation plug, which indicates that all calls for that line'are to be referred to the information operator. In such a case, the B operator inserts the plug 1 into the jack of a trunk circuit extending to the desk or switchboard of an intormation operator,

for example, into jack of the trunk circuit D (see Fig. 2). Relays 16 and 21 are thereupon operated over a circuit from battery through the lamp 15, Winding of relay 1G, sleeve contacts of the plug 14 and'the jack 20, righthand winding of relay 21 and contact 19 of slow operating relay 22 to ground. j: Relay 16, in operating, opens its normal. and closes its alternate contacts, whereupon ringing relay 23 operates over a circuit fron'i battery through the winding of ringing relay 23, normal contact of relay 2%,,

contact of trip relay 25, lower alternate contact of relay 16, contact of trunk relay 12, winding ofrelay 16, sleeve contacts of the plug 1d and the jack 20, right-hand Winding of relay; 21 and contact 19 of relay 22 to ground. The operationof ringingrelay 23 connects source of ringing current 26 through winding of trip relay to the trunk, circuit- D. The winding of ringing relay 23,- which is of. comparatively low' rcsista'nce, is now connected in parallel with thelamp 15, thereby extinguishing the lamp. Theoperation of relay 21 causes lamp 27, located at the information operators desk,

-to be lighted over-a circuit from battery through the lamp27, loft-hand normal contact of relay 28 and the contact ofielay 21 to ground.

I The information operator, observing the lighted condition of the lamp 2' 7,inserts plug 30 into jack31 of the trunk circuit D, whereupon relay 32 operates and lamp 33 lights ovena circuit from battery through lamp 33,

resistance 3 1, sleeve contacts of the plug 30 and the jack 31, lower winding of relay 32 and contact relay 22'to ground. Relay 32, in operating, bridgesrelay 36 across the tip and ring strands of the trunk circuit 1).

' Relay 36 is immediately traversed by ringing current and operates. Trip relay 25 also operates, rcmovlng a short c rcuit from aboutthe relay 24, which immediately op-- crates, locks up, and short-circuits ringing relay 23. rR1ngingrelay23: thereupon releases, disconnecting ringing'current from the trunk circuit D. Supervisory relay 37 then operates to include the left hand wind- .furnish thedesired information.

ing of trunk relay 12 in parallel with the right-hand winding thereof, thereby reduc.

ing' the resistance in circuit with the supervisory relay '13. Supervisory relay 13 thereupon operates to establish a shunt circuit, including resistance .38, for the lamp 9, which is thereby efi'aced. The operation of relay 32 already referred to, also causes the energization of relay 28 over a circuit from battery through the winding and rlght-hand normal contact of relay 28, lower contact of relay 32 and the contact of relay 21 to ground. Relay 28, upon being energized,

,opens the circuit of, and extinguishes lamp 27, and establishes a locking circuit for itself through its f left-hand alternate contact and contact'of relay21 to ground. Relays 28 and 36 being energized, relay 22 operates the jack 20 for a purpose which will more fully hereinafter appear. The opening of contact 35 of relay 22 removes ashort circuit from the upper winding of relay 32, Whereupon this winding is included in circuit with the lamp33, which is thereby extinguishedf The sequence of operation of the relays described, following the insertion of the plug 30finto the jack 31, is such that ringing current is disconnected from the trunk circuit D, and direct current substituted therefor before the talking circuit is completed through to the information desk, so that, if

the information operator has listening. key

4-0 actuated when plugging in, the usual disagreeable cllc-ks attending the tripping of ringing current'from an automatic ringing circuit, are not produced in the information operator-7s receiver. After the listening key a0 is actuated the informationoperator may converse with the calling subscrlber A and Should the information operator, after conversing withfsubscriberA, desire 'to communicate with the A operator to n instructions regarding the connection w the desired line, the information operator may, by repeatedly actuating a key 15, cause the intermittent lighting of the calling su' pervisory lamp 9; The actuation of. the key 15short-circuitsthe windings of relay 32, Which thereupon releases, disconnecting the relay 36 from. the tip and ,rin trands Of'the t1unlr circuit'D. Supervisory relay '37 thereupon releases its armature, thereby increasing the resistance in: circuit with the supervisory relay 13.] Supervisory relay 13 "with the trunk circuit D, and the information operator has connected the cord circuit .E with the trunk circuit D, attempt to rethen releases its armature, removing the shunt from the-callingsupervisory lamp 9, which thereupon lights. The lamp 33 is also lightedv upon the actuation of the key 45. Upon the disconnection of the relay 36 from the trunk circuit D, this relay releases its armature, causing the deenergization of relay 22, which opens'the talking circuit and in closing its upper and lower contacts, short-circuits the two condensers in ring by withdrawing the plug7 from and reinserting it into the jack'8, ringing current will not be connectedf'with the trunk circuit D. The withdrawal of'theplug 7 from the jack'S releases the trunk relay 12,

whereby the locking circuit of the rel'ay 24 cisflopenedu The reinsertion of the plug 7 into the jack 8 causes the, energization of trunk relay 12', whereupon'a circuit is establishedfor the ringing relay 2 3, but s1nce resistance139is now lncluded ln'this circuit,

ringing relay 23 does not'receive sufiicient current to cause it to move its-armatures. In thismanner, the apparatus functions to I prevent the connection ofiringing current with the trunk circuit D, if the trunk circuit C and the cord circuit E are already connected therewith whenthe cord circuit B is connected withthe trunk circuit 0. Therefore, if the information operators telephone set shouldbe connected with the talking circuit when the A operator connects with the trunk circuit, the inability to connect ringing current to trunk circuit D, pre vents the production of very severe and disagreeable clicks in the receiver of the information operator. i

The form of-trunk circuit shown in Fig.

3 may be employed between the B board and the information operators desk instead of thev trunk circuit and cord circuit of Fig.

2-. WVhen so. used, the insertion of the plug .14 of trunk circuit G into jack '50 of the trunkcircuit F causes the operation of relay .51 over a circuit from battery through the lamp 15, winding of relay l 6,-sleeve contacts of the plug 14 and the Jack50, lefthandnormal contact of relay 52 a-n d lefthand winding of relay- 51 to ground. Relay 51, in operating, causes lamp 53 to be lighted over'a circuit from battery through the right-hand contact of relay 51, righthand contact of relay 52 andthe lamp53 to ground. The relays'16 and 23 of the trunk circuit C operate as before described.v

The information operator, observing the lighted condition of the lamp 53, actuates listening key 54, thereby bridging relay 55 across the tipand ring strands of'the trunk circuit F in parallelwith the'condenser 56 and in series with the right-hand winding of relay 51. Trip relay 25 and relay55 thereupon operate. The operation of trip relay 25 causes'the disconnection of the ringing current as before described, and the operation of relay 55 causes the energization of slow-operating relay 57 to connect the information operators telephone set with the trunk circuit F. The actuation of the listening key 54 also causes'the operation of relays 52 and 58, the former over a circuit from battery through the" right-hand winding of relay 52 and contact 590f listening key 54 to ground, and the latter over a circuit from battery through the left-hand contact of relay 51, winding of relay 58 and contact 59 of'listening key 54 to ground.

circuit and includes its own left-hand winding in this sleeve circuit, thereby establishing a locking circuit for itself, and opens its right-hand contact, extinguishing the lamp 53. Relay 58, in operating, establishes a locking circuit for itself-through its alter nate contact and opens its normal contact,

thereby removing a short circuit of resistf jance 60, which is-thereby included in the sleeve and locking circuitof relay 52. The

purpose of connecting resistance-60 in the sleeve circuit of the trunk c1rcu1t F is to prevent the connection of rniging current to the trunk circuit 'F, should the A operator attempt to re-ring as before described. While listening key 54 is actuated, relay 51 is energized 'in' series. with relay 55, and supervisory relays-37 and '13 are energized while the calling supervisory lamp 9 is effaced. Upon restoration of the listening key 54 to normal position, relays 13, 37, 51, 55, 57 and.58-'release;-

What is claimed is:

1. A telephone exchange system comprising a trunkcircuit extending from a first to a second switchboard, aconnecting circuit 'at the first switchboard connected with'the trunk circuit, a source of ringing current thereat, a rlnging relay in the connecting circuit adapted when operated to connect the source of ringing current'with the trunk circuit, a normally open operating circuit for the ringing relay, means for closing Relay 52, in operating, disconnects the left 7 hand winding of relay 51 from the sleeve the-operating. circuit, a link circuit at'the circuit adapted when operated to connect the source of ringing current with the trunk circuit, a normally open operating circuit for the ringing relay,means for closing the operating-circuit, a link circuit at the sec- 0nd switchboard, and means responsive to the connection of the link circuit with the trunk circuit for rendering the operating circuit ineffective when subsequently closed by said first mentioned means. 4

3. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a connecting circuit at the first switchboard connected with thetrunk circuit, a source of ringing current thereat, a ringing relay in the connecting circuit adapted when operated to connect the source of ringing current with the trunk circuit, a normally open operating circuit for the ringing relay, means for closing the operating circuit, a link ciring-a trunk circuit extending from a first cuit at the second switchboard, a resistance coil, and means responsive .to the connection of the link circuit with the trunk circuit for including the resistance coil in the operating circuit, thereby to prevent the operation ofthe ringing, relay. 7 a

I 4. A telephone exchange system compristo a second switchboard, a connecting circuit at the first switchboard connected with the trunk circuit, a source of ringing current thereat, a ringing relay in the connecting circuit adapted when operated to connect the source of ringing current with the trunk circuit, a normally open operating circuit for the ringingrelay, means for closing the operating circuit, a link circuit at the sec- 0nd switchboard, a resistance coil, a short operating circuit therefor normally included in the circuit, and an electromagnetic relay responsive to the connection of the link circuit with the trunk circuit' for'opening the short circuitand including the resistance in the operating circuit,thereby to prevent the operation of the ringing relay. 7

5. A telephone exchangesystem comprising a trunk circuit extending from a first to" a second switchboard, a trunk circuit having normally open talking strands connect- 7 ed with the first trunk circuit at the second switchboard and extending therefrom.

to a third switchboard, a link circuitatthe first'switchboar'd, a; signaling device fortli'e link circuit operating upon the connection thereof with the first trunkcircuit, a link circuit at the third switchboard, an electromagnetic relay responsive to the connection of the second link circuit with the second trunk circuit for closing the, normally open talking strands thereof, means responsive to the closure of the talking strands for stopping the operation of the signaling device, and an operator controlled switch at the third switchboard for. causing the successive deenergization and energization of the electromagnetic relay'whereby the signaling device is intermittentlyoperated, 7 I

6. A telephone exchangesystem-comprising a trunk circuit extending from a first to a second .switchboard,a trunk cir'cuit' hav-V ing normally open talking strands connected with the first trunk circuit at the second switchboard and extending therefrom to a third switchboard, a link circuit at the first switchboard, a signaling-device forv the link circuit operating upon the connection thereof with the first trunk circuit, 'a link circuit at the third switchboard, an electromagnetic relay responsive to the connection of the second link circuit with thesecond trunk circuit for closing" the normally open talkf ing strands thereof, a resistance coil connected across the talking circuit upon the response of the electromagnetic relay, a signal control relay in the first link circuit 7 responsive to the connection of the resistance coil across the talking circuit to stop the operation of thesi'gnaling device, andan.

operator-controlled switch at the third switchboard forcausing the successive deenergization and energization of the electro'- magnetic relay whereby the signaling device'- is'intermittently operated. a V 7. A telephone exchange systemcoinprising a trunk circuit extending from a first to a second switchboard, a trunk circuit having normally open talking strands connected with the first trunk "circuit at the second switchboard and extending therefrom to a third switchboard, a link circuit at the first switchboard, a signaling device for the link circuit operating uponfthe'connection thereof with the first trunkcircuit, a link. circuit at the third switchboard, an electromagneticrelay responsive tofthe connection of the second link circuit with the second trunk circuit for closing the normally open talking strands thereof, a resistance icoil con-- -nected across the talking circuit-j'iipon the response of the electromagnetic relay, a signal control relay. in theifirs t link circuit controlled over the connected trunk circuit, a relay in the first trunk circuit energized upon the connectionof the resistance coil across these'c'ond trunkjcircuit to decrease the resistance in circuit with the sigmil-control relay whereby the signal-control relay is energized to stop the operation of the signaling device, and an operator-controlled switch at the third switchboard for causing the successive denergization and energization of the electromagnetic relay In witness w hereof, I hereunto subscribe 10 my name this 18th day of February A. D.,

ERIC R. LUNDIUS. 

